Transformerless Power Question

[William At MyBlueRoom]

I've attached a diagram from Microchips application notes on an X10 controller. I'd like to use a 120v to 6.3v transformer with a full bridge & 7805 instead.
The question is they've use earth as an electrical ground with a PTC to neutral. Can I hook the transformer primary directly to hot & neutral?

 

[Nigel Goodwin]

I've attached a diagram from Microchips application notes on an X10 controller. I'd like to use a 120v to 6.3v transformer with a full bridge & 7805 instead.
The question is they've use earth as an electrical ground with a PTC to neutral. Can I hook the transformer primary directly to hot & neutral?

Yes, assuming it's only feeding power to the circuit? - for X10 there needs to be some link back to the mains from the transmitter.